I should have been more clear: yes, biodiesel can come from things that compete with food crops, but the biodiesel made from waste is the only kind I endorse.

(Fun fact: the kind I use in my car is made from chicken fat, a byproduct of all the chicken processing plants we have here in northern Georgia.)

It's also possible to make synthetic gasoline, by the way, and I'm only endorsing making it from CO2 produced as a byproduct of something else (and, pointedly, not coal gasification or steam reforming of natural gas).

It does say some biodiesel is made from waste oil but also that...

...this local solution could not scale to the current rate of consumption.

That's where this part of my comment came in:

if we eliminated the need for the vast majority of cars by fixing our cities, then carbon-neutral ICE fuels might be able to meet a bigger fraction of the remaining need